Demographic Changes, Financial Markets, and the Economy

Abstract

It seems natural that the shifting composition of a nation’s population ought to influence GDP growth and perhaps also capital markets returns. As the baby boomers have aged, many people have studied past demographic data in an effort to extract indications for the future influence of the boomers on many aspects of the economy. We extend this body of literature by analyzing the effect of demographic changes on three measures of great importance for countries all over the world: real per capital PPP-adjusted GDP growth, stock market excess returns, and bond market excess returns. We confirm what others have already demonstrated, but we extract markedly more statistical significance by adapting a polynomial curve-fitting technique pioneered by Fair and Dominguez (1991), to this new purpose. In our work, we find that a growing roster of young adults (age 15–49) is very good for GDP growth, a growing roster of older workers is a little bad for GDP growth, and a growing roster of young children or senior citizens is very bad for GDP growth. We find surprisingly powerful results when we apply the same technique for exploring the links between demography and capital markets returns, net of the strong and well-documented effects of valuation and yield levels. Stocks perform best when the roster of people age 35–59 is particularly large, and when the roster of people age 45–64 is fast-growing. Bonds follow a similar pattern, with an age-shift: they’re best when the roster of people age 50–69 is growing quickly. We carry out three different forms of robustness checks, each of which provides statistical significance in different ways: applying different country weights, testing alternative demographic variables, and confirming GDP results on out-of-sample countries. It would be dangerous to forecast the future based on these results. Tacitly, we would be assuming that past relationships between demography and either GDP growth or capital market returns will hold unaltered in the future. However, given the high levels of statistical significance in the historical relationships, it is too tempting to resist exploring the possible implications for future GDP growth and capital market returns. These implications—with all the caveats that must necessarily be offered—are sobering, to say the least.